THE TRUE ARMY WORM AND ITS CONTROL. 9 
NATURAL ENEMIES. 
Most fortunately for the farmer, the army worm has many natu- 
ral enemies among the native insects, reptiles, birds, and mammals. 
INSECT ENEMIES. 
One of the commonest and most effective of its insect foes is a 
medium-sized gray fly! (fig. 6), closely resembling, and _ slightly 
larger than, the house fly. This parasite sticks its eggs fast to the 
skin of the caterpillar (fig. 2, b and e) 
and the quickly hatching maggots bore 
through the skin into the flesh, where 
they soon devour the entire inside por- 
tions of the army worm’s body. These 
flies multiply rapidly and often become 
so numerous as to control the army worm 
completely in a given locality. 
Another common insect foe is a very 
small wasplike creature (fig. 7),? which 
pierces the caterpillar with its sting or 
ovipositor, laying its eggs inside the 
army worm’s body, where they quickly 
hatch and, the maggots having eaten 
their fill, bore their way outward and ee ee dt eceaey oea ot 
spin little silken cocoons in a mass to- the wasplike parasite Apanteles 
gether, somewhat resembling grains of Dee aor es i 
rice entangled in a mass of cotton. This 
‘parasite is also sometimes numerous enough to be of great service in 
controlling the pest. _ 
Several other insect enemies serve more or less efficiently in 
combating the army worm. Some of these are shown in figure 2, 
ig, he 
fod 
Wie. 7. 
WILD BIRDS AND OTHER ENEMIES. 
According to the records of the United States Biological Survey, 
more than 40 species of native wild birds are known to eat the army 
worm in its various stages. Among the most important of these are 
the following: Crow blackbird or grackle, yellow-headed blackbird, 
chipping sparrow, bluebird, prairie hen, and European starling. 
Domestic fowls of all kinds will greedily devour the caterpillars and 
pupe if allowed to roam over infested fields. Skunks and toads also 
undoubtedly eat thousands of the army worms, both caterpillars and 
1 Winthemia quadripustulata Fab. 
2 Apanteles militaris Say. 
8 Calosoma Calidum Fab., (Ammophila) Sphex sp., and Enicospilus purgatus Say. 
